Detection of Ag+ ions via an anti-aggregation mechanism using unmodified gold nanoparticles in the presence of thiamazole

The present study proposed a novel and highly selective and sensitive method for Ag+ ion detection based on gold nanoparticles (AuNPs) anti-aggregation. Thiamazole can induce AuNPs aggregation due to electrostatic interactions, which result in color transitions in the AuNPs solution from red to blue. However, the presence of Ag+ ions results in the preferential combination of the pyridinic nitrogen of thiamazole with the Ag+ ions. In addition, the Ag+ ions oxidize the sulfhydryl groups(-SH), which inhibit AuNPs aggregation and prompt a color change from blue to red. As a result, the present study established a method for Ag+ ion determination by AuNPsthiamazole colorimetric probe based on the aforementioned anti-aggregation mechanism. The probe dynamic range was easily tuned via adjustments of the thiamazole amount. The relationship between the Ag+ concentration and AuNPs aggregation was monitored by ultraviolet-visible light (UV-Vis) spectroscopy at a dynamic range of 0.1 nM-9 mu M and at a detection limit of 0.042 nM. The river water and tap water recovery analysis validated the successful operation of this colorimetric sensor in environmental monitoring.

Automated summary

The study introduced a novel method for detecting Ag+ ions using thiamazole-induced AuNPs aggregation and color change mechanism. The probe demonstrated high selectivity and sensitivity in detecting Ag+ ions, with a detection limit of 0.042 nM. Environmental monitoring using this colorimetric sensor was successfully validated through river water and tap water recovery analysis.